u               horizontal wind speed along the north-south axis of a sonic anemometer, in m s-1
v               horizontal wind speed along the east-west axis of a sonic anemometer, in m s-1
w               vertical wind speed from a sonic anemometer, in m s-1
t               sonic anemometer temperature, in degrees C
q               water vapor density, in g m-3
CO2             carbon dioxide concentration in micromoles m-3
spd             the horizontal wind speed along the wind direction, in m s-1
wind speed      the horizontal wind speed along the wind direction, in m s-1
direction       wind direction, in degrees
vertical angle  angle of the wind to the geopotential surface, in degrees
ustar           friction velocity, in m s-1
H               sensible heat flux, in W m-2
LvE             latent heat flux, in W m-2